The invention relates generally to base members or substrate members having a central opening such as fluid nozzles, and, in particular, to a readily snap-fitted and readily disengageable cover plate for a fluid nozzle. The cover plate of this invention has application to, and is particularly adapted for, covering the exposed surface of a fluid nozzle body which includes a nozzle outlet rotatable to a variety of positions within a nozzle housing, to direct a jet of water, or water and air, in a given direction. The invention has particular application to nozzle designs such as shown in my prior art patent, U.S. Pat. No. 4,221,336 incorporated herein by this reference, as well as to other nozzle designs such as that shown in U.S. Pat. No. 3,997,116.